Washing machine and control method thereof

ABSTRACT

A washing machine and a control method thereof that are capable of improving washing and rinsing efficiencies of large-volume laundry (for example, bedclothes). When large-volume laundry is washed and rinsed, a drum is accelerated to a predetermined velocity such that the laundry clings to the drum, and therefore, wash liquid (or water) comes into uniform contact with the entire surface of the laundry while the laundry widely spreads, is stopped such that the laundry is separated from the drum, and is rotated in alternating directions to change the position of the laundry such that a surface of the laundry contacting the wash liquid (or the water) is turned, and therefore, even contaminants inside the laundry are removed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2008-0119416, filed on Nov. 28, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

One or more embodiments relate to a washing machine and a control method thereof, and, more particularly, to a washing machine and a control method thereof that are capable of improving washing and rinsing efficiencies of large-volume laundry.

2. Description of the Related Art

Generally, a washing machine (normally,.a drum type washing machine) is an apparatus, including a water tub to store water (wash water or rinse water), a cylindrical drum rotatably installed in the water tub to receive laundry, and a motor to generate a drive force necessary to rotate the drum, to lift the laundry in the drum along the inner wall of the drum and drop the lifted laundry, during the rotation of the drum, thereby washing the laundry.

When a user selects a washing course (for example, a normal course), the washing machine detects the weight (load amount) of laundry to decide the amount of wash water or rinse water, supplies water (specifically, wash water) and a detergent into the water tub according to the decided amount of wash water, and rotates the drum in alternating directions at a predetermined velocity (a rotation velocity at which the laundry is washed using head drop) for a predetermined time, to perform a washing operation by a force transmitted through wash liquid (water+detergent) to the laundry and to drop the laundry.

After the completion of the washing operation, the washing machine performs draining and intermediate spin drying, supplies water (specifically, rinse water) into the water tub according to a decided amount of rinse water, and rotates the drum in alternating directions at a predetermined velocity (a rotation velocity at which the laundry is rinsed using head drop; approximately 30 to 50 RPM) for a predetermined time, to perform a rinsing operation by a force to put the water into contact with the laundry and drop the laundry.

In the conventional washing machine performing the washing and rinsing operations through the above-described series of processes, the drum is rotated in alternating directions at a predetermined velocity for a predetermined time as in the normal course to perform the washing and rinsing operations even when large-volume laundry (for example, bedclothes) is washed. For large-volume, highly-hygroscopic laundry, therefore, the position of the laundry does not change but the laundry is rotated in the drum in a consistent shape, with the result that the washing is finished without the removal of contaminants (detergent leftovers or wash residues) inside the laundry. Also, a user may judge that only door glass is being washed, with the result that the user may not trust in washing efficiency.

SUMMARY

Therefore, it is an aspect of one or more embodiments to provide a washing machine and a control method thereof that are capable of by changing the position of large-volume laundry through a process including accelerating a drum to a predetermined velocity, stopping the drum, and rotating the drum in alternating directions, when washing and rinsing the laundry, thereby improving washing and rinsing efficiencies.

Additional aspects and/or advantages of one or more embodiments will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments.

In accordance with one aspect of one or more embodiments, there is provided a control method of a washing machine having a drum to receive laundry and a motor to rotate the drum, the control method including determining whether a large-volume laundry washing course has been selected, accelerating the drum to a predetermined velocity which causes the laundry to cling to the drum upon determining that the large-volume laundry washing course has been selected, and rotating the drum in alternating directions to change a position of the laundry.

The large-volume laundry washing course may include a bedclothes course or a towel course.

The predetermined velocity may be approximately 75 RPM or more.

The accelerating the drum and the rotating the drum may be performed during washing or rinsing.

In accordance with another aspect of one or more embodiments, there is provided a control method of a washing machine having a drum to receive laundry and a motor to rotate the drum, the control method including determining whether large-volume laundry washing or rinsing has been selected, accelerating the drum to a first velocity which causes the laundry to cling to the drum upon determining that the large-volume laundry washing or rinsing has been selected, and rotating the drum at a second velocity in alternating directions to change a position of the laundry.

The accelerating the drum may include causing a surface of the laundry to cling to an inner wall of the drum using a centrifugal force generated by the accelerating of the drum.

The control method may further include stopping the drum, after accelerating the drum, to separate the laundry from the inner wall of the drum.

The rotating the drum at a second velocity may include rotating the drum in alternating directions, after stopping the drum, to turn the surface of the laundry clinging to the inner wall of the drum.

In accordance with another aspect of one or more embodiments, there is provided a control method of a washing machine, including selecting a washing course by a user, determining whether the selected washing course is a course set to wash large-volume laundry, accelerating and rotating the drum at a velocity which causes laundry to cling to an inner wall of the drum upon determining that the selected washing course is the course set to wash large-volume laundry, and stopping and rotating the drum in alternating directions to change a position of the laundry.

The stopping and rotating the drum may include stopping the drum such that the position of the laundry changes from a first position to a second position, and rotating the drum in alternating directions such that the position of the laundry changes from a third position to a fourth position.

The stopping the drum and the rotating the drum may be repeatedly performed at least twice in the course set to wash large-volume laundry.

The first to fourth positions may be positions of the laundry changed to turn a surface of the laundry clinging to the inner wall of the drum.

The accelerating and rotating the drum and the stopping and rotating the drum in alternating directions may be performed during washing or rinsing.

The accelerating and rotating the drum which causes the laundry to cling to the inner wall of the drum may also cause the laundry to spread widely along the circumference of the drum.

The rotating of the drum may be at about 45 RPM in alternating directions.

The stopping of the drum may occur for a period of time equal to the rotating the drum in one direction before rotating the drum in another direction.

The accelerating and rotating the drum may be alternately performed with the stopping and rotating of the drum until a washing or rinsing time has lapsed.

The accelerating and rotating of the drum may be performed before the stopping and rotating the drum.

The stopping the drum and the rotating of the drum may be repeatedly performed for a predetermined number of times.

The predetermined number of times may depend upon a load amount of the laundry.

In accordance with a further aspect of one or more embodiments, there is provided a washing machine including a drum to receive laundry, a motor to rotate the drum, and a control unit to control the motor to accelerate the drum to a predetermined velocity and to rotate the drum in alternating directions, such that washing or rinsing is performed, for a large-volume laundry washing course.

The control unit may control a surface of the laundry to cling to an inner wall of the drum using a centrifugal force generated by accelerating the drum to the predetermined velocity.

The control unit may control the drum to be stopped, before rotating the drum in alternating directions after accelerating the drum, such that the surface of the laundry is separated from the inner wall of the drum.

The control unit may control the drum to be rotated in alternating directions, after stopping the drum, to turn the surface of the laundry clinging to the inner wall of the drum.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 illustrates a sectional view of the structure of a washing machine according to an example embodiment;

FIG. 2 illustrates a control block diagram of the washing machine according to an example embodiment;

FIG. 3 illustrates a control flow chart of the washing machine according to an example embodiment; and

FIG. 4 illustrates a graph of a drum velocity profile of the washing machine according to an example embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

FIG. 1 illustrates a sectional view of the structure of a washing machine according to an embodiment of the present invention.

Referring to FIG. 1, the washing machine includes a drum-type water tub 11 installed in a machine body 10 to store water (wash water or rinse water) and a cylindrical drum 12 rotatably installed in the water tub 11. The drum 12 has a plurality of spin-drying holes 13.

Outside the rear of the water tub 11 is installed a drive unit, i.e., a motor 16, to rotate a rotary shaft 15 connected to the drum 12 such that washing, rinsing, and spin-drying operations are performed in the drum 12. Inside the bottom of the water tub 11 is installed a water level sensor 17 to sense a frequency change depending upon the amount of water (water level) in the water tub 11 to sense the water level.

At the front of the machine body 10 is installed a door 19 having an entrance 18 through which laundry is put into or removed from the drum 12.

Above the water tub are installed a detergent supply unit 20 to supply a detergent and a water supply unit 30 to supply water (wash water or rinse water).

The detergent supply unit 20 has a plurality of partitioned spaces. The detergent supply unit 20 is installed at the front side of the machine body 10 such that a user easily puts a detergent and rinse in the respective partitioned spaces.

The water supply unit 30 includes a first water supply pipe 32 connected between an external water supply pipe 31, through which water (wash water or rinse water) is supplied into the water tub 11, and the detergent supply unit 20, a second water supply pipe 33 connected between the detergent supply unit 20 and the water tub 11, and a water supply valve 34 mounted on the first water supply pipe 32 to control the supply of water. In this structure, water is supplied into the water tub 11 via the detergent supply unit 20, and therefore, a detergent is supplied from the detergent supply unit 20 into the water tub 11 together with the water.

The washing machine further includes a drainage unit 40 to drain contaminated water, i.e., drainage liquid, from the water tub 11. The drainage unit 40 includes a first drainage pipe 41 connected to a drainage port 11 a formed at the bottom of the water tub 11 to guide the drainage liquid outside, a drainage pump 42 mounted on the first drainage pipe 41, and a second drainage pipe 43 connected to the outlet of the drainage pump 42.

FIG. 2 illustrates a control block diagram of the washing machine according to an example embodiment. The washing machine further includes an input unit 50, a control unit 52, a drive unit 54, and a velocity detection unit 56.

The input unit 50 inputs operation information selected by a user, such as a washing course (for example, a bedclothes course or a towel course), spin-drying RPM, and the addition of rinsing, to the control unit 52.

The control unit 52 is a microprocessor to control the overall operation of the washing machine based on the operation information inputted from the input unit 50. The control unit 52 stores the amount of wash and rinse water, motor RPM and operation rate (motor on-off time), and washing and rinsing time set according to the amount of load (the weight of laundry) in the selected washing course. To wash large-volume laundry, the control unit 52 controls the drum 12 to be accelerated to a first velocity (a rotation velocity at which laundry clings to the inner wall of the drum, and therefore, the laundry is not separated from the inner wall of the drum; approximately 75 RPM or more), to be stopped, and be rotated in alternating directions at a second velocity (a rotation velocity to change the position of the laundry; approximately 45 RPM) a predetermined number of times such that the position of the laundry is changed.

That is, after the amount of wash and rinse water set for the washing and rinsing is supplied, the control unit 52 controls the operation of the motor 16 such that the drum 12 is accelerated to the first velocity at which laundry clings to the inner wall of the drum, and therefore, the laundry is not separated from the inner wall of the drum (approximately 75 RPM or more) in one direction, is stopped, and is rotated in alternating directions at the second velocity (approximately 45 RPM) a predetermined number of times (a number of times set according to the amount of load; approximately 4 times), which are repeatedly carried out for the washing and rinsing time, and therefore, wash liquid or water (rinsing water) comes into uniform contact with the surface of the laundry while the position of the laundry is changed.

For large-volume laundry, the drum 12 is accelerated to the first velocity such that the laundry clings to the drum 12, and therefore, the wash liquid (or the water) comes into uniform contact with the entire surface of the laundry while the laundry widely spreads. When the drum 12 is stopped, and therefore, the laundry is separated from the drum 12, the drum 12 is rotated at the second velocity in alternating directions to change the position of the laundry such that the surface of the laundry contacting the wash liquid (or the water) is turned, and therefore, even contaminants inside the laundry are removed. Consequently, the washing and rinsing operations are effectively performed.

The drive unit 54 drives the motor 16, the water supply valve 34, and the drainage pump 42 according to a drive control signal of the control unit 52. The velocity detection unit 56 detects the rotation velocity of the drum 12 driven by the motor 16, and inputs the detected rotation velocity of the drum 12 to the control unit 52.

Hereinafter, the operation of the washing machine with the above-stated construction and a control method thereof will be described.

FIG. 3 is a control flow chart of the washing machine according to an example embodiment, illustrating an algorithm to improve washing and rinsing efficiencies in washing and rinsing large-volume laundry (for example, bedclothes or towels).

Referring to FIGS. 2 and 3, when a user puts laundry in the drum 12, and selects operation information, such as a washing course 100 (for example, a bedclothes course or a towel course), spin-drying RPM, and the addition of rinsing, based on the kinds of the laundry, the operation information selected by the user is inputted to the control unit 52 through the input unit 50.

The control unit 52 controls washing and rinsing to be performed according to the operation information inputted from the input unit 50. At this time, the control unit 52 detects the amount of load (the weight of laundry) put in the drum 12, and sets the amount of washing and rinsing water, motor operation rate (motor on-off time), and washing and rinsing time based on the detected amount of load.

Subsequently, the control unit 52 determines in operation 102 whether the washing course selected by the user is a washing or rinsing operation for a course set to wash large-volume laundry (for example, a bedclothes course or a towel course). When it is determined that the washing course is the washing or rinsing operation, the control unit 52 controls the water supply unit 30 (FIG. 1) to supply the set amount of washing or rinsing water. Specifically, the water supply valve 34 is opened, and water (wash water or rinse water) is supplied 104 into the water tub 11 (FIG. 1) via the first and second water supply pipes 32 and 33 (FIG. 1). When it is determined that the washing course is not the washing or rinsing operation, operation 102 may repeat.

Subsequently, in operation 106, the control unit 52 senses the level of water supplied into the water tub 11 (FIG. 1) through the water level sensor 17 to determine whether the level of the supplied water is a predetermined water level (a water level decided depending upon the set amount of wash or rinse water). When it is determined that the level of the supplied water is not the predetermined water level, the control unit 52 controls water to be continuously supplied through the water supply valve 34.

When it is determined at operation 106 that the level of the supplied water is the predetermined water level, the control unit 52 controls the supply of water to be stopped 108, and controls the motor 16 to accelerate the drum 12 in one direction 110. At this time, the rotation velocity of the drum 12 is detected by the velocity detection unit 56, and the detected rotation velocity of the drum 12 is inputted to the control unit 52.

Subsequently, the control unit 52 determines whether the rotation velocity of the drum 12 detected by the velocity detection unit 56 has reached a predetermined first velocity in operation 112 (a rotation velocity at which laundry clings to the inner wall of the drum, and therefore, the laundry is not separated from the inner wall of the drum; approximately 75 RPM or more).

When it is determined at operation 112 that the rotation velocity of the drum 12 has not reached the first velocity, the motor 16 may be driven for approximately 7 seconds, as shown in FIG. 4, until the rotation velocity of the drum 12 reaches the first velocity.

As the motor 16 is driven until the rotation velocity of the drum 12 reaches the first velocity, the laundry clings to the drum while spreading widely, with the result that the entire surface of the laundry comes into uniform contact with wash liquid (for the washing operation) or water (for the rinsing operation), and therefore, the washing or rinsing effect is enhanced.

On the other hand, when it is determined at operation 112 that the rotation velocity of the drum 12 has reached the first velocity, in operation 114, the control unit 52 controls the motor 16 to be stopped such that the rotation of the drum 12 is stopped for approximately 3 seconds, as shown in FIG. 4. As the drum 12 is accelerated to the first velocity and is then stopped, the position of the laundry changes from a first position at which the laundry clings to the inner wall of the drum 12 to a second position at which the laundry is separated from the inner wall of the drum 12.

Subsequently, in operation 116, the motor 16 is driven again, and the drum 12 is rotated at a second velocity (a rotation velocity to change the position of the laundry; approximately 45 RPM) in alternating directions, as shown in FIG. 4.

As the drum 12 is rotated in alternating directions, the position of the laundry at which the laundry clings to the inner wall of the drum 12 changes from a third position (for example, outside) to a fourth position (for example, inside). Consequently, the surface of the laundry contacting the wash liquid (for the washing operation) or the water (for the rinsing operation) is turned, with the result that even the contaminants inside the laundry are removed, and therefore, the washing or rinsing efficiency is improved.

At this time, in operation 118, the control unit 52 determines whether the number of rotations of the drum in alternating directions is a predetermined number of times (a number of times set according to the amount of load; approximately 4 times). When it is determined that the number of rotations of the drum in alternating directions is not the predetermined number of times, the drum 12 continues to be rotated in alternating directions.

Rotating the drum in alternating directions a predetermined number of times is carried out to approximately change the position. The predetermined number of times may be changed into a value previously set by the control unit 52 depending upon the amount of load.

When it is determined at operation 118 that the number of rotations of the drum in alternating directions is the predetermined number of times, the control unit 52 controls the rotation of the drum 12 in alternating directions to be stopped, and in operation 120, determines whether predetermined washing or rising time has elapsed.

When it is determined at operation 120 that the washing or rinsing time has not elapsed, the procedure returns to operation 110 to continue the washing or rinsing operation while the drum 12 is accelerated to the first velocity in one direction, is stopped, and is rotated in alternating directions at the second velocity the predetermined number of times, which are repeatedly carried out for the washing or rinsing time, and therefore, the wash liquid or the water (the rinsing water) comes into uniform contact with the surface of the large-volume laundry while the position of the laundry is changed, as shown in FIG. 4.

On the other hand, when it is determined at operation 120 that the washing or rinsing time has elapsed, and in operation 122, contaminated water is drained from the drum 12 and the water tub 11 (FIG. 1), and spin drying is performed.

As is apparent from the above description, when large-volume laundry is washed and rinsed, the drum may be accelerated to a predetermined velocity such that the laundry clings to the drum, and therefore, wash liquid (or water) comes into uniform contact with the entire surface of the laundry while the laundry widely spreads, is stopped such that the laundry may be separated from the drum, and is rotated in alternating directions to change the position of the laundry such that even contaminants inside the laundry are removed, whereby the washing and rinsing efficiencies are improved.

Although a few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A control method of a washing machine having a drum to receive laundry and a motor to rotate the drum, the control method comprising: determining whether a large-volume laundry washing course has been selected; accelerating the drum to a predetermined velocity which causes the laundry to cling to the drum upon determining that the large-volume laundry washing course has been selected; and rotating the drum in alternating directions to change a position of the laundry.
 2. The control method according to claim 1, wherein the large-volume laundry washing course comprises a bedclothes course or a towel course.
 3. The control method according to claim 1, wherein the predetermined velocity is approximately 75 RPM or more.
 4. The control method according to claim 1, wherein the accelerating the drum and the rotating the drum are performed during washing or rinsing.
 5. A control method of a washing machine having a drum to receive laundry and a motor to rotate the drum, the control method comprising: determining whether large-volume laundry washing or rinsing has been selected; accelerating the drum to a first velocity which causes the laundry to cling to the drum upon determining that the large-volume laundry washing or rinsing has been selected; and rotating the drum at a second velocity in alternating directions to change a position of the laundry.
 6. The control method according to claim 5, wherein the accelerating the drum comprises causing a surface of the laundry to cling to an inner wall of the drum using a centrifugal force generated by the accelerating of the drum.
 7. The control method according to claim 6, further comprising stopping the drum, after accelerating the drum, to separate the laundry from the inner wall of the drum.
 8. The control method according to claim 7, wherein the rotating the drum at the second velocity comprises rotating the drum in alternating directions, after stopping the drum, to turn the surface of the laundry clinging to the inner wall of the drum.
 9. A control method of a washing machine, comprising: selecting a washing course by a user; determining whether the selected washing course is a course set to wash large-volume laundry; accelerating and rotating a drum at a velocity which causes laundry to cling to an inner wall of the drum upon determining that the selected washing course is the course set to wash large-volume laundry; and stopping and rotating the drum in alternating directions to change a position of the laundry.
 10. The control method according to claim 9, wherein the course set to wash large-volume laundry comprises a bedclothes course or a towel course.
 11. The control method according to claim 9, wherein the stopping and rotating the drum comprises: stopping the drum such that the position of the laundry changes from a first position to a second position; and rotating the drum in alternating directions such that the position of the laundry changes from a third position to a fourth position.
 12. The control method according to claim 11, wherein the stopping the drum and the rotating the drum are repeatedly performed at least twice in the course set to wash large-volume laundry.
 13. The control method according to claim 11, wherein the first to fourth positions are positions of the laundry changed to turn a surface of the laundry clinging to the inner wall of the drum.
 14. The control method according to claim 9, wherein the accelerating and rotating the drum and the stopping and rotating the drum in alternating directions are performed during washing or rinsing.
 15. The control method according to claim 9, wherein the accelerating and rotating the drum which causes the laundry to cling to the inner wall of the drum also causes the laundry to spread widely along the circumference of the drum.
 16. The control method according to claim 9, wherein the rotating the drum rotates the drum at about 45 RPM in alternating directions.
 17. The control method according to claim 9, wherein in the stopping and rotating the drum, the stopping of the drum occurs for a period of time equal to the rotating the drum in one direction before rotating the drum in another direction.
 18. The control method according to claim 9, wherein the accelerating and rotating the drum is alternately performed with the stopping and rotating the drum until a washing or rinsing time has lapsed.
 19. The control method according to claim 9, wherein the accelerating and rotating the drum is performed before the stopping and rotating the drum.
 20. The control method according to claim 11, wherein the stopping the drum and the rotating the drum are repeatedly performed for a predetermined number of times.
 21. The control method according to claim 20, wherein the predetermined number of times depends upon a load amount of the laundry.
 22. A washing machine comprising: a drum to receive laundry; a motor to rotate the drum; and a control unit to control the motor to accelerate the drum to a predetermined velocity and to rotate the drum in alternating directions, such that washing or rinsing is performed, for a large-volume laundry washing course.
 23. The control method according to claim 22, wherein the control unit controls a surface of the laundry to cling to an inner wall of the drum using a centrifugal force generated by accelerating the drum to the predetermined velocity.
 24. The control method according to claim 23, wherein the control unit controls the drum to be stopped, before rotating the drum in alternating directions after accelerating the drum, such that the surface of the laundry is separated from the inner wall of the drum.
 25. The control method according to claim 24, wherein the control unit controls the drum to be rotated in alternating directions, after stopping the drum, to turn the surface of the laundry clinging to the inner wall of the drum. 